ET- Einstein Telescope Technology for the third generation
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Transcript of ET- Einstein Telescope Technology for the third generation
GWADW- May, 10-15, 2009 1
ET- EINSTEIN TELESCOPE
TECHNOLOGY FOR THE THIRD GENERATION
Harald Lück, AEI Hannover EU contract #211743
´06 ´07 ´08 ´09 ´10 ´11 ´12 ´13 ´14 ´15 ´16 ´17 ´18 ´19 ´20 ´21 ´22
Virgo
GEO
LIGO
LISA
E.T.
Virgo+
E-LIGO
Advanced Virgo
GEO HF
Advanced LIGO
DS PCP Construction Comm.
Hanford
Livingston
Launch Transfer data
data
You are here
1st Generation 2nd Generation 3rd Gen.
GW Timelines
Site Prep.
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In this talk no discussion of
Interferometer size As big a finances allow? How big is that?
Over-ground vs under-ground (J. Harms, Jo Van der Brand, D. Rabeling) Will low frequency performance goals really require underground operation ?
Low frequency suspensions (R. Nawrodt) Newtonian Noise Cryogenic operation (W. Johnson, K. Kuroda)
Is cryogenics really needed to achieve the goals or is room temperature sufficient (at least for high frequencies) ?
Non gaussian beams (A. Freise) QND tricks (H. Müller-Ebhardt) Xylophone: collocated multi-narrowband vs single-broadband
detector (S. Hild, R. DeSalvo)
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Technologies Some (good?) candidates for the third generation
Substrate material: Silicon Gratings & wave-guide coatings (H. Lück) Quantum noise:
Squeezing (A. Khalaidovski) Laser (N. Man)
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Mechanical Q of substrate materials
Nawrodt et al.
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SILICON (Properties)
Vanishing CTE@ 20k & 125K
Low thermal lensing @ low temp.Fused silica 2E-5 / K @ 300 K No thermoelastic noise
Temperature [K]
Dn/
dT
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Physical properties of silicon
Thermal conductivity Silicon Specific heat Silicon
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Properties of silicon / silica
Thermal conductivity fused Silica
Specific heat Silicon / fused silica
1/101E4
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Siliconlow absorption @ 1550nm expected
from M. Green and M. Keevers, Optical properties of intrinsic Silicon @ 300K, Progress in Photovoltaic research and Applications, Vol. 3, 189-192 (1995)
Wikipedia.com
Max. Diameter currently 450mm
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Mechanical lossesof the coatings
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Coatings on Silicon Refractive index of Silicon @ 1550nm ~ 3.48 @ 300K Refractive Index of SiO2 ~ 1.44 fewer layers needed due to difference in refractive
indeces
SiSiO2Si
Coating
SiO2Si
Substrate
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Diffusion of Oxygen
SiO2
Coating
SiO2Si Si
SiO
SiO
SiO
Si
SiO
Substrate
High absorption of SiO might be a problem for SiO2
coatings on Silicon substrates
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Nanostructured Surfaceswaveguide coatings
substrate substrate
Monolithic 100% reflection “coating”[Brückner et al., Opt. Lett., 33, 264 (2008)]
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Promising new results
R > 99.8%, private communication, IAP Jena, R. Schnabel
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cryst. quartz, 3“ 12 mm, 11670 Hz
Mechanical losses of gratings
Nawrodt et al., New Journal of Physics 9 (2007) 225
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Extracted coating/grating losses
Nawrodt et al., New Journal of Physics 9 (2007) 225
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Squeezing
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11.5dB @ 5MHz10
64 n
m
Vahlbruch et al. PRL 100, 033602 (2008)
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Low frequency squeezing
Chelkowski et al., PRA 75, 043814 (2007)
1064
nm Shot noise
Squeezed noise
electronic darknoise
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Squeezing @ 1550 nm15
50 n
m
Mehmet et. al.: arXiv:0902.0670v1 [quant-ph]
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Fragile Squeezed States Influence of losses
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Laser available today, 1064 nm
Solid state laser: laser diode pumped solid state laser (AdvLIGO): 210W Nd:YAG, less than 12% in higher order modes, almost finished
design for reliable long-term operation 3 E-9 /sqrt(Hz) power stability @ 10Hz, rf noise: 1dB above SN of
100mA @ 9 MHz
fibre laser: ytterbium doped photonic crystal fiber amplifier using a single-
frequency Nd:YAG non-planar ring oscillator seed source 148W, less than 8% in higher order modes 13 November 2006 / Vol. 14, No. 23 / OPTICS EXPRESS 11071
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Laser available today, 1550 nm
Solid state laser: -
fibre laser: Erbium fibre laser, ~2 W, poor reliability
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Laserplans
1064 nm: Reach 1kW within next 5 years RIN < 1 E-9 /√Hz
1550 nm: 150 W within next few years
2022
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Refractive index of silicon
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Refractive Index fused silicahttp://www.sciner.com/Opticsland/FS.htm
Wavelength, µm 0.2 0.22 0.25 0.3 0.32 0.36 0.4 0.45 0.5
Refractive Index 1.55051 1.52845 1.50745 1.48779 1.48274 1.47529 1.47012 1.46557 1.46233
Wavelength, µm 0.55 0.59 0.60 0.65 0.7 0.75 0.8 0.85 0.9
Refractive Index 1.46008 1.45846 1.45804 1.45653 1.45529 1.45424 1.45332 1.4525 1.45175
Wavelength, µm 1.0 1.1 1.2 1.3 1.5 1.6 1.7 1.8 1.9
2.0
Refractive Index 1.45042 1.4492 1.44805 1.44692 1.44462 1.44342 1.44217 1.44087 1.43951
1.43809
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The brute force approachStefan Hild
S. Hild et al, http://arxiv.org/abs/0810.0604